Compressed laminated product and process of making the same



" Inaccordance with my Aimproved procedure Y Patented Feb. 18, 1930 'f"STATE il'. Y'OfiIillS'HCEIMER, v'01? KWEST ORANGE, rN'E'W JERSEY,ASSGNOR TO ISPRUCO- LI-TE QORPORATION, INC., OF WEST ORANGE, NEW JERSEY,:A vCORPOEIATION OF i N 'o Drawing.

fr NEW JERSEY Linate .PAT-ENT oFF-ics This invention relates tocompressed coinfpositeproductsof laminated material hav- Ving a yfibrousstructure and to lprocess for producing s uch products. Theobj ect ofthe invention is to render such products stable with Vrespect to varyingconditions of temperature yand humidity of the environment in which theproduct is made, used, or through .which Ait zmay `he transported.

i0 netware `(ce Patent No. 1,465,383 of August 21,1923) compositeproducts have IAbeen made by. compressing. under great pressure, a stackor pile of layers of material, such vas lumber, having a binderinterposed bev tween adjacentlayers. By maintaining the Av,- ,differentWays to make various,products,.such

as pulleyagears, and the like. i Theseproducts itvvas vrobserved .undersome conditions exhibited signsof-distortion and tended to rendertheinnotentirely satisfactory for their y.intended use. Y The yc auseof such:distortion was not readily detectable. Numerous efforts pto-remedy thecondition provedfutile.

I havenoW discovered that the causefof the ,distortingeects developed inthe material a0 isto be foundfin excessive variationsof the moisturecontent ofthe producty such as oc j cury when said product is made inthe usual .mannen Such .products vwhen `shipped to 4 .Warm or dryiclimatesexhibit` al greater tend- .fencyftovvard auto-distortion thanwhen used in -thefilocality Where the `product ismann- Vfactured. Theresultant evaporation of moisf uct is used 'in a more humid .environmentturevvhich takes place ina drieror a warmer environment is apparently amore i powerful or energetic i-agent causing distortion thanathsfabsorptioiiof .moisture when the prod- These :factsled meto modify`,the method vli. e -retof or e. employed in the particulars hereinafteri referred to.

I can impart greatstability and enhanced util-itytothefinal product bydrying Athe raw materahsuchaswood, to` wub-normal d@- greeiat er1,iiitrasuctorysstage ofztlieprccess `priate to the. production ofvApplication 4.filed `Getober 2.8, 1927. Serial No. 229,521.

templates controlling the moisture content of raw or intermediatematerial at some vstage prior to fabrication into the finished productso that the moisture content of-theiinished product is lower than thatof the environment Y where such productisto be used or shipped.

'The moisture control is preferably exercised at an introductory stageof the process, and [I havefound it to be especially advantageous todiymaterial, such as Wood,prior to the addition of the binder substance.After the wood, or the like, is sub-normally dried and isimpregnated,coated, or covered with the binder, it is piled inlayers inthe usual.manner toform a stack ofmaterial in which the grain of some or all ofthe adjacent layers extends at differingfangles This stack of Vlayers isthen subjected to thefcustomary pressure operation which compresses thestack to a fractional portionof its original volume or height. Whenthebinder between the various layers of the stack has set, the block ofcompressed composite product is fabricated in any ymanner suitable orappron the desired final product. v *i The following specific exampleofa pre ferred mode of y carrying v my invention into practice is givenfor illustrative purposes .and ,for ,a better understanding of `the,iii-

'A select iouof -a material having a fibrous structure, suoli as Wood,like spruce, is first made by Ygiving due consideration tothecharacteristicsand properties required inthe Afinal product. Theselected spruce yWood is preinto boards or strips having dimensionsappropriate to the product to be fabricated.

lflflienarticles such as pulleys, gears, and the like are to bemanufactured, the boards are approximately four feet long,jabout four totwelve inches Wide, 'and a fraction of an incli thick, although otherdimensions may be se-d lected depending on the particular conditions andcircumstances, as one skilled in the art Will readily understand. rIliemoisture content of the Wood varies Within Wide limits but the-usualcommercial air or kiln dried Wood contains approximately ten totwentyi'ive vpercent moisture.

Such so-called dry Wood is, for the pur-V poses of this invention, to beregardedasgbeing Wet Wood. By noiv dryingtliisvet'yvood to a subnormaldegree in any approvediiianner, a truly dried vWood. is obtained whichris almost bone dry or contains up to say about two percentofrinoisture.l In carrying outthis dryingoperation care inust/betaken tokeepthe graii'iand the pores/ofthe Wood openfor free absorption of abinder and not to case-harden the Wood because a Wood liaving a.case-hardened surfacegreatly -im'pedes or even. prevents thesubsequently necessary absorption of abinder. Proper drying underobservance of the foregoing conditions can l be carried out in anystandard drying appasolvent may be employed to coat,v cover, im-

pregnato, saturate,V etc., the dried boards.

YWhichever bonding composition is employed,

it should be mobile at ordinary Working tein-r peiatuie's and pressures`as contrasted with immobile bonding agents sucli'aspowdered' glue,.solidresins, or sheet Vriibbei-'oisimilar immobile substances.Bonding,composition .in the inobile or iuidst'ate will readily enter andbe drawn into the pores of the ivoodivlien applied at ordinaryVtemperatures and preseures so as to accumulate, Within the structure ofthe Wood, a substance iinportedby the bonding composition Whichmay-serve as a lubricant for the i'ibres duri'iigftlie period ulieii thelibres inoveupon tlieiiiselvesrvduring subsequently applied enormous'pressure.

One method is tocover the.' superficialsur` y faces-ofthe boardin anyWell knoivii coating -inacliine With al Yca 'seiii type Aglue orV,vvitli a binder containing-casein, linie,sodiuin s'ili cate,v andanieta-llic salt Ydis'solvedin.Water in appropriate proportions.-l A."Llarge` variety yof casein glues may beused but a casein glue inside-inaccordance with oney of the formulae Aof the ForestfProductsLaboratoryfhas been found to give 'satisfactoryresults.' "flVli'ateVc'lvariety of casein gluel is used, it is preferable to apply it to theWood While the glue' is still in the freshly prepared state. .l/Vhen acasein binder of the aforesaid casein type is applied rtothe subnormallydried'spruceboards, the

moisture content of the latter increases, but

only to the extent of sayV approximately sixV to ten percent which is,hovveveiglower than the highest permissible jdegree of moisture contentrequiredfor stability, in the final product.

The glue-coated boardsai-e stacked upon 'each other, preferably at anangle toeacli other in adjacent layers'and iii'ay manner. suitable forgiving the requisite strength and Vthe desired shape to the Vfinishedblock product. In the manufacture-of pulleys,i gears,

or tlielike, the glue-'coated boards inpadjacent layers may beset atright anglesfto each other, Wliile'for` other products the *angularTarrangement may be difl'ei'eiit.v After apile of boards has been stackedin the aforesaid 'mannen it subjected to an lenormous pressure in ordertof compress the ibresof the Wood into intimate contact ivitlijeachother.;

rlliiscoinpression operationinay be conveniently eected by the use ofpressure rolls or hydraulic pressure. 1 f

In carrying out the compressionof the pileu of boards ina hydraulicpress,` forexainple,

ay relatively small pressureis irst applied vand is'inaintained untilthe fbinderoii the outer surfaces of the pile hasassunied a conditionivhere it Will not be squirtedou'tfroni betiveen'adj aceiit boards whenlthe pressurer is subsequently increased; YAfter tlie'binder has acquiredateinporaryset,'as"itg\vere, the pressure is progressively increaseduntil the lso desired ,enormous pressure has been Yreaclied. p

During the course of the aforesaid process,"

the outer surfaces of tliepile may besubjected to artificial drying whendesired. Tlieproduct of these operations is-a rigidlcoinposite v blockof compressed boards. l'This-rigid coniposite block may tlieii befabricated in any? suitable -inanner appropriate tothe production of thedesired article.

fr fabricated articley constitutedof comeV iis f pressed compositeliiinberwhi'cli basl-been,V

prepared in accordance jvvitli my invention-" possesses astabilityWith-respect5tomoisture that makes thearticlel particularly adapted 'touse iii 'relatively dryand/or relatively hot 'en "vironinents.VvIiilthislivay, articles'can be Vproduced in one geographicalregioin andlshipped to Vanother Where climatic 'conditions are entirelyv different,-o'r the linislied articles canbe used is avariety of industrialoperations olr commercial.-situationsvunder varie.. ous external.conditions Withoutideveloping VAdeleterious deterioration or.distortionjof"theV product.

In some instaiieesit maybe desirable to' further modify n thefinoirsture A,contentfcff the compressed vc oinposite material ffu'the-risc y f mal degree in the first stage of manufacture,

this sub-normal drying step may be carried out after the compressedblock is finished.

Y In that case the ywood constituting the block will as yetcontain tookmuch moisture which, when my invention 1s practised, will need to beremoved before the final products are made from thematerial constitutingthe block.

I claim: 1. The process of producing compressed composite products whichcomprises prepar-` ing a multiplicity'of units of material having afibrous (structure, surfacing said units with a bonding compositionwhich is mobile at ordinary working'temperatures and pressures wherebysaid composition partly flows or is drawn into the interior of thefibrous structure ofthe material, arranging said units in a stack withalternate layers set at an angle to each other so that the contacting`surfaces of said units prior to compression of the stack make anadhesive connection with each other While part of the bondingcomposition is present in the interior of the fibrous material in theyseveral uncompressed units, subjecting said in correlation with atleast one of said steps,

reducing the moisture content of the material pto sucha degree that theresultant product will have a lower aggregate percentage of moisturethan that which prevails in any environment wherein thel product isnormally adapted to'be used.

2. The process of producing compressed composite products whichcomprises preparing a multiplicity of'unit's of material having a.fibrous structure, drying the said fibrous materialto reduce themoisture content thereofto such a degree that even upon addition ofmoisture in subsequent stages of the processy the're'sultant productwillhave a lower aggregate percentage 'of moisture than that which prevailsin any environment wherein the product is normally adapted to be used,surfacing said unit-s of fibrous material with a bonding compositionwhich is mobile at ordinary working temperatures and pressures wherebysaid compositionpartly flows or is drawn into the interior of thefibrous, structure of the material, arranging said units in a stack withalternate layersset' at an angle to each other so that the contactingsurfaces of said 'units prior to compression of the stack make anadhesive connection with each other while part' of the bondingcomposition is present in the interior' of the fibrous material inv theseveral 'uncompressedainita subjecting said stack in theaforesaidcondition to an enormous pressure to' compress the material ofthe stack and to'bring the fibres of said'rmat'erial' into closefrictional'contact with each other, and maintaining pressure on saidstack until the bonding composition has permanently set ,and the fibrousmaterial has assumed a stable condition. f

3. The process of producing compressed composite products whichcomprises preparing a multiplicity of units of material having a fibrousstructure, drying the said fibrous material to reduce the moisturecontent thereof to such a degree that even upon addition of moisture insubsequent stages of the process the resultant product will have a loweraggregate percentage of moisture than that which prevails in anyenvironment wherein the product is normally adapted to be used,surfacing said units offibrous material with a freshly prepared aqueouscasein glue which is mobile at ordinary working temperatures andpressures whereby said composition partly fiows or is drawn into theinterior of the fibrous structure of the material, arrangingy said unitsin a stack with alternate layers set at an anffle to each other so thatthe confacting surfaces of said units prior to compression of the stackmake an adhesive connection with each other while part of the bondingcomposition is present in the interior of the fibrous material in theseveral uncompressed units, applying a relatively small pressure tovsaid stack until the casein glue on the outer surfaces of the stack hasassumed a condition where-it will not be squirted out from betweenadjacent units when the pressure is subsequently increased, thensubjecting said stack in the aforesaid condition to an enormous pressureto compress the material of the stack and to bring the fibres of saidmaterial into closefrictional contact Awith each other, and maintainingpressure on said stack until the bonding composition has permanentlyrset and the fibrous material has assumed a stable condition.

V4:. In the art of producing composite laminated compressed productsfrom lumber having a fibrous structure, the improvement which comprisesreducing the lumber to a non-case-hardened subnormally ldry conditionhaving its moisture content reduced to a value within the range notgreater than 2%, then applying to a surface of the thus dried lumber abonding composition which is mobile at ordinary working temperatures andwhose moisture content plus the residual moisture content stillremaining in the wood after the operationv first set yforth is limitedso as still tobe lower than that which prevails in any environmentinfwhich the product s normally adapted to yloeused, affording aLn op- Y5 portunity for said Composition to find its Way partiallyinto theporous structure of the librous subnormally dry lumber, forming a stackofsaid lumber with adjacent surfaces bearingsuoh bonding Composition,applying size- 10 reducing pressure to the stack and maintainingpressure on the stack until the bonding composition has equired apermanent set, In testimony whereof I have hereunto set my hand.. s 15 pLAWRENCE J. OLLESHEIMER.

